Professional street trials rider and Red Bull athlete Danny MacAskill’s new documentary web series, “Imaginate,” which features his visit to DISC Sports and Spine, debuted on Tuesday. The Scottish-born athlete filmed the series while he was dealing with both a back and knee injury that severely limited his time on the bike. In the first installment, cameras followed him as he traveled to Southern California to meet with Dr. Robert Bray about the two injuries. In the episode, Dr. Bray discovers that the low back pain stems from an old injury that hasn’t healed, and is at the same time, complicating his recovery from a knee injury.